Webb30 jan. 2024 · The resistor is rated at 1.9K/W, I'll be using thermal paste rated at 0.11K/W, and then I need a heat sink which is the unknown in the equation. The effective operating temperature range goes up to 250C, but I'd rather stay lower. 40* (1.9+0.11+X)+30 < 250 76+4.4+40X+30 < 250 110.4+40X < 250 40X < 139.6 X < 3.49 Webb5 maj 2011 · Re: Taking 2 1/2 watt resistors and wiring them together to make a 1w r. Yes. If you need them in series (2 times the value of 1), then the current is the same, but voltage is halved. So each has half power. If you need them in parallel (1/2 of the value of 1), then the voltage is the same, but the current is halved.
Standard Resistor Values ( 5%) - ch00ftech
Webb23 juli 2024 · The generic resistors are used for the very low current of operations and are generally used in standard ambient temperatures such ... The power rating of this resistor needs to be P = I 2 R or P = 2 2 x 0.05 = 0.2 Watt. The close value of the shunt resistor will be 50 mili-ohms, 1% rated, 0.25 Watt. But instead of 0.25 Watt, 0.375 ... Webb26 feb. 2013 · If you look at the values, you will find that 100 Ohm is less than 128 Ohm (that we calculated) and is quite risky. The next higher easily available value is 220 Ohm. When you substitute R=220 in the equation I=V/R I = V/R I = 3.2/220 ~= 14mA You will get the value of the current to be around 14mA. LED’s operate between 10-25mA. tabitha show stopper porcelain
Resistor Values Resistor Standards and Codes Resistor Guide - EE Po…
WebbThis calculator will select the closest standard resistor value, from 1% 5% or 10% standard EIA values, calculates the error, and prints out a table of the standard values for the given tolerance. The EIA E number is the number of logarithmic steps. For example, for E12 has twelve steps between any power. Webb• (Wht, Org, Blu, Brn, Grn) Measured resistance = 9.38 kΩ • (Red, Blk, Wht, Grn, Vio) Measured resistance = 20.86 MΩ Assume that all five-band resistors listed here use the precision color code as opposed to the military 5-band code where the fifth band indicates resistor reliability. Question 11 Webb9 dec. 2015 · If you know the voltage across the resistor it's P=V²÷R. Take as an example the common resistor for an LED. Assume a 2V LED and a 220 ohm resistor. With a 5V total voltage the voltage across the resistor would be 5-2=3V. So the power would be (3²)/220 = 9/220 = 0.041W so you could quite happily use a 0.125w (⅛w) resistor for that job. tabitha show cast